I have wondered the same thing but have never seen one break. I have seen ones that have been bottom hung with a tight set drag on the rigger that are stretched right out so that they would have little snubbing function left in them. Once they are stretched out or the metal hardware (usually the attachment clip) on them is bent up from being run through or jammed on the rigger pulley, it is time to replace them. The ones from Scotty are about the smallest diameter ones you will find, and I have still not seen one break. If you want more reassurance, Trotac has sold snubbers that come in larger diameters and are much stronger. Don't go so large that they are too strong to provide much snubbing function on the little rigger balls that sports guys use. Basically they are shock absorbers, that take the stress off rigger braid/cable, terminal gear and attachment points.